Dialkyl 2-(dialkylhydroxyphenyl)-2-butendioates



United States atent Ofiice 3,277,152 Patented Oct. 4, 1966 This is a continuation-in-part of copending application Serial No. 276,192, filed April 29, 1963 and now abandoned.

This invention relates to esters which are useful in the stabilization of organic material normally subject to oxidative deterioration and in particular to esters containing alkylhydroxyphenyl groups.

The compounds of the present invention may be represented by the formula (lower) alkyl HO -C-COalky1 C H-C O Oalkyl (lower) alkyl In the above formula and throughout this specification, the term alkyl is intended to embrace branched or straight chained saturated hydrocarbon groups having from 1 to 24 carbon atoms. When qualified by the term (lower), the alkyl group will contain no more than eight carbon atoms.

These compounds are utilized in an amount from about 0.005 to about by Weight of the total composition,

to provide protection against oxidative deterioration as well as that caused by light and heat. They may be used alone or in combination with other additives such as dilauryl thiodipropionate, ultraviolet light absorbers, other antioxidants, dyes, pigments, chelating agents and the like.

Materials which are stabilized according to the present invention include synthetic organic polymeric substances, both homopolymeric and copolymeric, such as vinyl resins formed from the polymerization of vinyl halides or from the copolymerization of vinyl halides with unsaturated polymerizable compounds, e.g., vinyl esters, a,,8-unsaturated acids, a,,B-unsaturated esters, cap-unsaturated ketones, ,fl-UIISBIHI'EllEd aldehydes and unsaturated hydrocarbons such as butadienes and styrene; poly-a-olefins such as polyethylene, polypropylene, polybutylene, polyisoprene and the like, including copolymers of poly-w olefins; polyurethanes such as are prepared from polyols and organic polyisocyanates; polyamides such as polyhexamethylene adipamide; polyesters such as polymethylene terephthalates; polycarbonates; polyacetals; polystyrene; polyethyleneoxide; and copolymers such as those of high impact polystyrene containing copolymers of butadiene and styrene and those formed by the copolymerization of acrylonitrile, butadiene and/or styrene. Other materials stabilized according to the present invention includes lubricating oil of the aliphatic ester type, e.g., di- (2-ethylhexyl)azelate, pentaerythritol tetracaproate and the like; animal and vegetable derived oils, e.g., linseed oil, fat, tallow, lard, peanut oil, cod liver oil, castor oil, palm oil, corn oil, cotton seed oil and the like; hydrocarbon material such as gasoline, both natural and synthetic, diesel oil, mineral oil, fuel oil, cutting fluids, Waxes, resins and the like; fatty acids; varnishes, soaps; and the like.

The compounds of the present invention may be prepared by treating a dialkylphenol with a dialkyl ester of acetylenedicarboxylate in the presence of a base such as potassium t-butoxide. The required dialkyl acetylenedicarboxylate may be prepared by any of the usual esterification techniques from acetylenedicarboxylic acid and the appropriate alkanol of from 1 to 24 carbon atoms.

Suitable phenols include 2,6-di-t-butylphenol, 2,5-di-tbutylphenol, 2,6 dimethylphenol, 2 methyl-6-t-butylphenol and the like.

The following examples will serve to further typify the nature of this invention but should not be construed as a limitation thereof. In these examples parts are by weight unless otherwise specified and temperature is expressed in degrees Centigrade. The relation of parts by weight to parts by volume is as that of grams to cubic centimeters.

Example 1 To a stirred solution under nitrogen of 6.78 parts potassium t-butoxide in parts by volume of dry tbutanol is added 37.1 parts of molten 2,6-di-t-butylphenol. To the resulting green mixture is added a solution of 10.65 parts dimethyl acetylenedicarboxylate in 30 parts by volume of dry t-butanol over a 30 minute interval with continuous stirring.

The resulting mixture is stirred and heated at 5560 for 20.5 hours, then cooled and acidified with dilute hydrochloric acid and treated with ether and water. After the phases are separated, the aqueous phase is extracted with two fresh portions of ether. The original ether solution and ethereal extracts are combined, Washed with water, aqueous sodium chloride and dried over sodium sulfate. After removal of the drying agent, the solvent is evaporated to yield dimethyl 2-(3,5-di-t-butyl-4-hydroxyphenyl)-2-butendioate, B.P. l84/ 0.8 mm. Crystallization from cyclohexane-hexane yields the product as a solid, M.P. 142143.

Example 2 In a similar fashion, diethyl acetylenedicarboxylate and dipropyl acetylenedicarboxylate are substituted for dimethyl acetylenedicarboxylate in the procedure of Example 1 to yield diethyl 2-(3,5-di-tbutyl-4-hydroxyphenyl)-2-butendioate and dipropyl 2-(3,5di-t-butyl-4- hydroxyphenyl) -2-butendioate, respectively.

Likewise by substituting, 2,5-di-t-butylphenol and 2,6- dimethylphenol for 2,6-di-t-butylphenol in the procedure of Example 1 there are respectively formed dimethyl 2- (2,5-di-t-butyl-4-hydroxyphenyl)-2-butendioate and dimethyl 2- (3 ,5 -dimethyl-4-hydroxyphenyl) -2-butendio ate.

What is claimed is:

1. Compounds of the formula:

(lower) alkyl III H O- C C O Oalkyl HCOOalkyl (lower) alkyl wherein alkyl contains up to about 24 carbon atoms and (lower) alkyl contains up to about 8 carbon atoms.

2. Compounds of the formula:

HO C O Oalkyl EC 0 Oalkyl M wherein alkyl contains up to about 24 carbon atoms.

3. Dimethyl 2 (3,5-di-t-butyl 4 hydroxyphenyl)-2- butendioate.

References Cited by the Examiner UNITED STATES PATENTS 2,293,309 8/1942 Robin et al 260475 LORRAINE A. WEINBERGER, Primaly Examiner. DANIEL D. HORWITZ, Examiner. S. B. WILLIAMS, Assistant Examiner. 

1. COMPOUNDS OF THE FORMULA: 